In many situations it is necessary to be able to take notes or to write when the illumination is insufficient to clearly see the paper being written upon, for example during slide or movie presentations, in the nursing units of hospitals in the middle of the night, and at night in an airplane cockpit.
Certainly this problem is not new, and there have been many devices proposed and constructed to solve it in the past. Examples of some of these prior art devices are disclosed in the following U.S. Patents, U.S. Pat. No. 3,502,850, "Writing and Lighting Instruments" by G. Kocham, issued Mar. 24, 1970; U.S. Pat. No. 3,604,917, "Ballpoint Pen Light", by Oron Laverne Schmidt, issued Sept. 14, 1971; U.S. Pat. No. 3,963,914, "Combination Writing Implement and Flashlight", by Scott M. Browning, issued June 15, 1976; U.S. Pat. No. 4,016,414, "Writing Device Incorporating Illuminating Means", by Scott M. Browning, issued Apr. 5, 1977; U.S. Pat. No. 4,028,540, "Flashlight Marking Implement", issued June 7, 1977; and U.S. Pat. No. 4,168,521, "Writing Implement With Self-contained Illumination", by Harold F. Bajusz, issued Sept. 18, 1979.
In these prior art systems, it is typical to provide a light bulb and battery combination, the typical means of affecting electrical connection between the battery and the light bulb being by a pressure activated switching system. Such connection is conventionally made either by activating a separate switch or by moving the pen body or cap to force physical connection between the battery and other electrical conductors in the system. Also, some have used a spring-clip, for example as might be used to frictionally hold the pen inside a shirt pocket, as the movable element of a switch. However, none of these systems uses the length of the spring-clip as an electrically conductive element in the switching system for making electrical contact between the battery and the lightbulb. In addition, none of these devices is particularly well adapted to be mounted on a clipboard, a convenience that would be very useful.